Natural sponges, like the one in the picture above, are actually animals taken from the sea! The sponges in your home, however, were most likely never living things. Most sponges used in kitchens today are made from unnatural materials.

Sponges

Sponges
(
Figure
below
) are classified in the phylum
Porifera
, from the Latin words meaning "having pores." These pores allow the movement of water into the sponges’ sac-like bodies. Sponges must pump water through their bodies in order to eat. Because sponges are
sessile
, meaning they cannot move, they filter water to obtain their food. They are, therefore, known as
filter feeders.
Filter feeders must filter the water to separate out the organisms and nutrients they want to eat from those they do not.

The sponges often have tube-like bodies with many tiny pores.

You might think that sponges don't look like animals at all. They don't have a head or legs. Internally, they do not have brains, stomachs, or other organs. This is because sponges evolved much earlier than other animals. In fact, sponges do not even have true tissues. Instead, their bodies are made up of specialized cells that do specific jobs. For example, some cells control the flow of water, in and out of the sponge, by increasing or decreasing the size of the pores.